| Wheat stripe rust, caused by Puccinia stiiformis f. sp. tritici (Pst), is one of the mostimportant diseases threatening to global wheat production. At present, cultivation ofdisease-resistant varieties is the most effective, economic and environment security method tocontrol wheat stripe rust. However, most of named resistance genes from wheat have beenovercomed by new virulent Pst races, and conventional cross-breeding often lags behind thevariation of wheat strip rust.Therefore, original strategies must be changed, and new rustresistance gene resource must be explored to ensure food safety in production and achievedurable disease control of wheat stripe rust in our country.Non-host disease resistance (NHR) is the most common formof disease resistanceexhibited by plants against the majority of potentially pathogenic microorganisms. NHR isformed in the long process of evolution, which is the most basic, oldest and most widespreadform of disease resistance. Unlike R gene mediated resistance, NHR is not for some virulentraces of pathogenic microorganisms, but for all the virulent races of the pathogen, and eventhe pathogen of the same genera are resistant. NHR also has the very strong stability, and itwill not lost resistance along with the variation of pathogen. Thus, mining the NHR generesources for stripe rust durable resistance and control has a good application prospect.Rice (Oryza sativa L.) is the only gramineous crops can not be infected by rust and becultivated large-scale. The resistance of rice to rust is considered to be NHR. Therefore, thisstudy used histology, proteomics and genetics methods to research non-host interactionsystem of rice-wheat stripe rust, deepening the understanding of plant NHR mechanism, andalso laying a good foundation for eventually obtaining rust resistance genes of rice.1. Non-host interactions between Pst and two rice subspecies were characterized using23rice varieties, including11japonica and12indica. Results showed that the infected fungalstructures were easily produced in the leaves of indica, whereas only several substomatalvesicles and primary infection hyphae were observed in the leaves of japonica. This resultindicated that indica is less resistant or more susceptible to Pst than japonica. Hydrogenperoxide accumulated in the initial phase of japonica–Pst interaction but not in indica–Pstinteraction. A set of reactive oxygen species (ROS)-related genes was also induced in response to Pst infection, suggesting that ROS activation is one of the major mechanisms ofnon-host resistance of japonica to Pst;2. Two-dimensional electrophoresis (2-DE) technique was used to identify the Pst NHRrelated proteins in rice. Rice leaf proteins from the24and48hours post inoculated treatmentsor from the mock inoculated controls were analyzed. The comparative analyses revealed atotal of31spots that showed significant difference (P <0.05) in protein abundance betweenCYR32inoculated plants and mock controls.These proteins involved in signal transduction,biotic and abiotic stress, photosynthesis, energy metabolism, protein and nucleic acidsynthesis, and redox reaction. Among them, glyceraldehyde-3-phosphate dehydrogenase andphosphoglycerate kinase belonged to the glycolytic pathway andparticipated in the stressresponse induced by ROS. The up-regulated of ascorbate peroxidase protein OsAPx8suggested active oxygen scavenging system in rice also involved in NHR against to Pst. Theincrease of FtsH protease and heat shock protein Hsp70showed that the interaction of FtsHand Hsp70caused over-production of H2O2and hypersensitive response. The identified ofrice Lr10resistance protein indicated this gene might be involved in recognize the rusteffectors and then activated incompatible hypersensitive response, and also indicated there issome intrinsic relationship between host resistance and NHR;3. To identify the genes and genetic mechanism in rice for non-host resistance to Pst, across was constructed between the relative susceptible rice mutant line crr1(compromisedresistance to rust1) and a resistant rice line Zhonghua11. The two parents and F2segregationpopulation were inoculated with CYR32in greenhouse, and then4QTLs related tosubstomatal vesicle formation (Qsv01, Qsv06a, Qsv06b and Qsv10) and3QTLs related tocolony areas (Qca07, Qca10and Qca11) were detected using inclusive composite intervalmapping (ICIM) method. Interestingly, Qsv10and Qca10were mapped on the same locationof chromosome10, the LOD values of them were14.85and11.49, respectively. And theirvariation contributions were36.21%and28.48%, respectively. The genetic distance ofmapping interval was only0.95centiMorgen, therefore, Qsv10and Qca10should becontrolled by the same gene. According to the previously results of rice resistance genes andQTLs, consider that Qsv10/Qca10was a novel resistance loci. This result laid a solidfoundation for cloning the non-host resistance genes in rice for the future;4. The key genes (TaG3Pdhs and TaGLI1) in glycerol-3-phosphate (G3P) biosynthesiswas cloned from wheat cultivar Suwon11. Quantification analysis revealed that G3P levelswere significantly induced in wheat leaves challenged by the avirulent Pst race CYR23. Thetranscriptional levels of TaGLY1and TaGLI1were likewise significantly induced by avirulentPst infection. Furthermore, knocking down TaGLY1and TaGLI1individually or simultaneously with barley stripe mosaic virus-induced gene silencing (BSMV-VIGS)inhibited G3P accumulation and compromised the resistance in the wheat, whereas theaccumulation of salicylic acid (SA) and the expression of the SA-induced marker gene TaPR1in plant leaves were altered significantly after gene silencing. These results suggested thatG3P contributes to wheat systemic acquired resistance (SAR) against stripe rust, and providedevidence that the G3P function as a signaling molecule is conserved in dicots and monocots.Meanwhile, the simultaneous co-silencing of multiple genes by the VIGS system proved to bea powerful tool for multi-gene functional analysis in plants. |
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